It is well known that engines designed with two intake valves per cylinder are capable of producing high horsepower levels. This capability is maximized when both ports receive an equal amount of fuel. A single injector spraying into both tracks or runs of a siamesed intake manifolding arrangement, such as shown in FIG. 1A, can economically provide for this fueling requirement.
Stringent NOx emission control requirements can be met without fuel efficiency loss if the burn rate in the engine is sustained at an optimal level while introducing high rates of charge diluting EGR to suppress knocking. Desired control of burn rate can be achieved by blocking most or all of the air flow to one of the ports. If a flow deactivator or control valve is installed into the siamesed port arrangement shown, for example, in FIGS. 1B and 1C upstream of the injector, the burn rate improvement is inadequate because the siamesing connection still allows sufficient air to cross over into and bypass the supposedly deactivated port. Good burn rate control has been achieved with separated ports, one of them being deactivated, such as is shown in FIG. 1D, with fuel being injected into the active port. However, the drawback to this arrangement is that when both ports are open, only half of the air is impregnated with fuel. This leads to some power and fuel economy losses.
If a port deactivator or control valve is applied to a siamesed port layout downstream of the siamesed section, again FIG. 1A, the active port induces high swirl rate into the cylinder; however, some concern might be had about fuel being injected to both the active and the inactive port. Experimental results with separate ports, one of them being deactivated, however, indicate that half of the fuel can continue to be injected into the inactive port without detrimental effects. The reasons for this are:
1. Backflow during overlap between the exhaust and intake cycles, and a slight leakage through the deactivated valve will carry the fuel into the cylinder.
2. Swirl induced by the biasing of the air flow into one passage is so beneficial for mixing and burn rate that the possible detrimental effect of fuel stratification is completely eliminated.
It follows from the above that there can be two alternative resolutions that could achieve optimal results.
1. Twin porting with a very small siamesed section, adequate only for the installation of a unique injector having two spray holes about 8-10 mm apart so that fuel is introduced to both ports from one injector. The port deactivation valve would be upstream of the injector.
2. Conventional siamesed porting with a deactivation valve downstream of the siamesed, section, such as is illustrated in FIG. 1A.
This invention is directed to the use of a one-piece deactivation or control valve that can be installed into the cylinder head intersecting all of the multiple intake valve passages and situated close to the intake ports, thereby facilitating the use of conventional siamesed porting and fueling, such as is shown in FIG. 1A.
Takii et al. U.S. Pat. No. 4,766,866 shows a charge intake system similar to that shown herein in FIG. 1C. More particularly, it shows a cylinder with three intake valves 24, 25, 26 receiving a charge from a passage 31, with individual runners or logs 37 and 38 upstream of a fuel injector 32. One of each pair of the logs can be controlled by a butterfly type valve 41, 42, the valves being mounted on a common shaft 43. It should be noted that the valves in this case are upstream of the fuel injector and also outside of the cylinder head, and require separate mounting of the valve, per se, to a shaft, in contrast to the construction to be described.
Aoyama et al. U.S. Pat. No. 4,703,734 shows a charge intake system having two intake valves per cylinder connected by separated passages to a common intake passage leading into the cylinder head. In this case, a fuel injection valve 30 is mounted in one passage and a deactivation or flow control valve 8 is mounted in the other passage, in a manner similar to that shown in FIG. 1D herein. The butterfly type valves are fixed to a common shaft. Here again, as in FIG. 1D herein, only half of the air is impregnated with fuel when both ports are open.
Aoyama et al. U.S. Pat. No. 4,628,880 is another example of an engine having two intake valves per cylinder with separated intake passages, one containing a deactivation or control valve, and the other the fuel injection valve. The disadvantages of this construction are as described above in connection with U.S. Pat. No. 4,703,734.
Yagi et al. U.S. Pat. No. 4,317,438 and Motosugi et al. U.S. Pat. No. 4,240,387 are examples of engines with one or more intake valves and deactivation or control valves regulating the charge flow into the cylinders. However, in each case, there is no fuel injection valve and the mixture is supplied by a carburetor. Furthermore, in each case, the multiple control valves appear to be individually attached to a single shaft outside of the cylinder head.
Sugiyama U.S. Pat. No(s). 4,512,311 and 4,576,131, both show a multi-intake valve per cylinder engine having a common intake runner and separated siamesed passages to the intake ports. FIG. 4 shows one of the passages being controlled by a deactivation or control valve to regulate the flow from a fuel injector mounted upstream of both passages. It will be noted, however, that the individual deactivation or control valves appear to be individually attached to a common shaft; and that the shaft is mounted outside of the cylinder head and therefore not close to the intake ports, and is not of a simplified construction, such as is to be described hereinafter. The outside mounting increases the length of the divided passages and, therefore, eliminates the use of conventional siamesed passages.
Walchle et al. U.S. Pat. No. 3,750,698 is cited merely as an illustration of a valve having a polytetrafluoroethylene coating for reducing friction.